Pyrotechnic device



Dec. 3, 1935. W, L. KANN 2,022,770

PYROTECHNIC DEVICE Filed April 6, 1955 Patented Dec. 3, 1935 UNITEDSTATES ATENT oFFicE 9 Claims.

This invention relates to pyrotechnic devices, and more particularly tosuch articles known in the trade as salutes and toy torpedoes.

It is a general object of the present invention to provide novel andimproved pyrotechnic devices of the type mentioned and novel methods ofmanufacturing the same.

More particularly it is an object of the invention to providepyrotechnic devices in which the 'explosive compound is enclosed in amo-nolithic casing of hardened plastic material having the quality ofbreaking or shattering into iine particles as a result of the explosionwhereby large flying parts are avoided.

Another object of the invention resides in the provision of apyrotechnic device including a capsule enclosing the explosive compoundand which is encased in an outer cover of plastic material formedthereabout while soft and permitted to harden.

A further object of the invention resides in the enclosing of a mass ofexplosive compound and detonating means within a monolithic plasticcasing during the forming of the casing.

An important feature of the invention as applied to toy torpedoesresides in filling the capsule completely full of explosive material andsome detonating agent such as gravel and then encasing it in a coveringof plastic material and permitting the material to harden, and in soselecting this material that it shrinks materially on hardening to applypressure on the walls of the capsule and compress the particles ofgravel to render them immobile'under ordinary handling of the device,thereby eliminating the danger of premature explosions during shipmentby shifting o-f the gravel particles in respect to each other.

Another important feature of the invention resides in certain methods ofassembling the pyrotechnic devices wherein the explosive is placed,

in a capsule which is then supported or suspended centrally in a moldand molten plastic material poured into the mold and the supporting orsuspending means removed before the plastic material hardens, therebypermitting the encasing of the capsule in a monolithic or unitary coverwhich will resist the expanding gases resulting from the explosionsubstantially uniformly in all directions to produce the maximum reportand to better insure against the flying of large portions or segments ofthe casing.

Other and further features and objects of the invention will be moreapparent to thoseskilled in the art upon a consideration of the accom-Figure 3 is a similar view showing the torpedo 15 V` after the casinghas cooled and shrunk away from the walls of the mold and compressed thecapsule and its contents; Y

Figure 4 is a central section through a modified form of torpedo; 20

VFigure 5 is an elevation of a capsule and fuse for a salute, partlybroken away to show the contents; and

Figure 6 is a section of the salute capsule showing the casing formed bydipping. 25

Toy torpedoes and salutes must be manufactured with both a view tosafety to the user and manufacturer as well as a low cost. To insuresafety to the user, it is essential that the covering or casing shallnot remain in large pieces 30 which might fly as a result of theexplosion and inflict serious injury. To provide safety duringmanufacture and shipment, it is essential that the possibility ofaccidental explosion be reduced i to a minimum, and to provide low costit is neces- 35 sary to eliminate insofar as possible manual operationsand to'reduce the total number of operations to a minimum. The torpedoesand salutes of the present invention, when constructed according to theexemplary methods to be de- 40 scribed, meet all three of therequirements satisfactorily.

t will be understood that in the specification where the term salute isused, it refers to any explosive Ytoy which isY ignited by the use of afuse 45 and in which the main or primary purpose is to place when thecasing is violently impacted as by throwing it against a sidewalk, wall,or the like. The only difference in the two types of toys may be in themeans for igniting the'explosivethe'z,

first requiring the application of fire and the second necessitating animpact or shock.

In the drawing, several methods and specic forms of torpedo and salutehave been shown by way of example only. The torpedo of Figures 1, 2 and3 consists essentially in four components, the outer casing (D, thecapsule Il, the explosive compound I2, and the igniting means I3, whichmay be variously termed impact devices, ignition means, impact ignitingmeans, or more simply gravel since that is the common ingredient usedfor the purpose.

The gravel and explosive compound are en-V closed in the capsule, whichfor conveniencemay comprise two telescoping parts as shown, and thewhole is encased in the monolithic outer casing or cover, preferably ofspherical configuration a1- though any desired outer form may beselected.

In the manufacture of a torpedo, the explosive material is firstselected. It may consist of any suitable explosive composition such ascommonly used in torpedoes of this type. A satisfactory composition forthe purpose includes at least two ingredients, one an oxidizing agentand the other a readily oxidizable substance. The rst may be potassiumchlorate and the second sulphur, but in most cases it isY preferred toadd to these two ingredients a third or sensitizing ingredient such, forinstance, as antimony sulphide. 'I'he proportionsof this ingredientcontrol the sensitivity.

The impact igniting means may be any suitable hard granules, of anabrasive character if desired, but for the sake of convenience andcheapness, sized gravel is customarily used. It is preferred to have thesize of the gravel such that but a few particles are in the capsule, forinstance, not many more than six to ten.

The capsule Il may be formed of any suitable tenacious material which isbendable or exible and can b-e readily made and handled. A satisfactoryform comprises a pair of telescoping paper or cardboard cups punched tothe shape shown and one 4iitting over the other with sufficientcloseness so that friction holds the parts together temporarily afterthey have been telescoped.

In the lling operation the smaller of the two cups isY supplied with therequisite amount of gravel, and explosive compound either pre-mixed,

or with appropriate proportions of the separate ingredients which willlater be mixed by a tumbling process or in the normal handling operationof the torpedoes. For the purpose of this invention, it is desirablethat the gravel particles substantially ll the cup so that when the capor cover is applied, there is none or only a very small empty space l5remaining-the smaller this space, the better. The explosive need notcompletely fill the interstices between the particles of gravel.

The covering material to provide the casing for the capsule has twofunctions, iirst, Yto. somewhat reinforce the capsule and hold the partsthereof together to provide a louder explosion, and second, to give apleasing contour, size and appearance to the finished article. It isadvan-l tageous that this covering be'substantially monolithic in orderthat there be no planes or areas of cleaving which will permit it toseparate readily into several large particles which will fly. It ispreferred to apply this casing by casting or molding it about thecapsule, but it may also be applied by dipping the capsule into a moltenmass in one o r a series of successive operations to build up therequisite thickness. Then again, the ma- For instance, the casing maywell be made from rosin, stearic acid, parafn,

waxes of many forms and types, sulphur, pitch compositions, or any oneor more of the above ingredientstogether with a iiller such as an inertground pigment or other colored pigments as iron oxide, lead oxide,chromium oxide, zinc oxide; or llers which are inert and withoutsubstantial coloring characteristics, such as wood 20 iiour, groundpaper, cellulose, or other suitable and cheap ingredients. Under certainconditions, mixtures as forinstance, clay and glue,

wood our and silicate of soda, and the like, may

be used. The main purpose is to obtain a composition for the. casingwhich is substantiallyn moisture-proof and which if heat softened ismolten Vat a temperature not so high as to ignite the explosivecomposition when formed about the capsule, remembering that the coolingis rather rapid and the capsule oerssome protection. The

material should not be soft at anynormally en` countered atmospherictemperatures, norshould it be sticky. If not of the heat softened type,the

plastic material should be quick-drying. Pleasing colors are desirablebut notressential and can be obtained by some of the iilling ingredientsmentioned above. Y Y

The most important feature of the casing, however, is that itshouldcontract or shrink very materially on hardening from its molten orplastic 'st ate for two purposes, rst, in order to place the wholecapsule under strong compressive stresswhich will cause it to engage themass of explosive materialand gravel and hold the same substantiallyunder Apressrureat all times, thus preventing substantial relativemovement of the gravel particlesin respectY to each other and insuringYaga'instrigr'ntion o f the explosive compound except V,upon Violentimpact, which will displace the'gravel particles due to momentum thereofand/or to deforming the casing; and second, in order that it mayseparate cleanly from the "mold, if a mold isused. 4

In the molding operation, use is made of a lower mold 26 preferablyhaving a vsemi-spherical upwardly extending cavity 2| and an upper moldportion`22 having a downwardly extending and correspondingly sizedsemi-spherical cavity 2 3. In order that the capsuleand its charge maybe held centrally of the spherical cavity of the combined mold parts,the lower portion of the mold is providedrwith Vthree vertical holes 24to accommodate the three slender metal pins 25Y which at their lower orouter ends are'secured to a carrying bar 26. The upper ends Vof, thepins` lie in a horizontal plane and are preferably arranged at theapices' of an equilateral triangle lessV in extent than the bottom areaof the capsule.

' When the bar Tais positioned as shown in Figure l, the upper ends ofthese pinsare properly positioned to receive the loaded capsula,

after which the upper portion of the mold is put in position and securedand the molten plastic 3ol i material is poured in through the iillingVopening 30. During this operation entrapped air may escape through theopenings 3l. As soon as the plastic material has been poured in to llthe mold as shown in Figure 2, the pins are withdrawn to the positionillustrated in that View and the molten material allowed to close up thespace recently occupied by thepins. In Figure 2 it will be seen thatthere is still a small space above the gravel and explosive and thatthev plastic material completely fills the mold.

In Figure 3 the mold is shown after cooling of the plastic, which takesplace very rapidly because of the chilling eect of the metal walls ofthe mold, so that actually the torpedoes can be removed very shortlyafter the pouring operation. The shrinking eifect of the plasticmaterial causes it to draw away from the mold as shown at 32, leaving abright, clean, shiny surface on the torpedo and entirely freeing it fromthe mold so that it can be readily picked out when the upper half of themold is removed. Any sprue remaining, as at 33, may be broken or cut oiTas desired. The effect of the shrinkage of the material on the capsulemay be noted in Figure 3, for it is shown as reduced in size and at allpoints in engagement with the material filling the same so that thegravel is held rigid under compression and relative movement of theparticles thereof is prevented.

In Figure 4 is shown an embodiment of a torpedo which differs in somerespects from that shown in Figures 1, 2 and 3 but which functions inthe same manner. It contains the same capsule and charge, but as a rstcovering for the capsule there is a layer 35 of extremely tenaciousmaterial preferably placed on the capsule by a dipping operation. It maycomprise a plastic having bers incorporated therein or it may be someVery tenacious plastic, as for instance, rosin, combined with aplasticizer. If this material remains sticky for any appreciable periodafter dipping, the coated capsules can be thrown on a revolving orshaking table covered with some powdered material to prevent sticking ofthe capsules together. This extremely tenacious coating reinforces thecapsule suciently to provide a complete torpedo insofar as explosivequalities are concerned, but for the purpose of giving it a suitableconguration and appearance and a sufficiently large size to beattractive to the purchaser, the outer covering or casing 36 isprofrangible so that the very complete explosion re*Y sulting from therupture of the tenacious casing will cause the outer covering to bebroken into minute fragments so that none of them will fly and bepotential sources of danger.

Since the inner coating can well be made waterproof, this outer casing35 can be a simple mixture of glue and a ller such as powdered clay,sawdust, wood flour, cellulose, paper pulp, or the like. Under theseconditions it will readily retain a coloring material eitherincorporated is left out and a fuse 40 inserted through one wall of thecapsule, as shown in Figure 5, preferably prior to filling andassembling thecapsule parts. This fuse may stick out through the openingused for lling the mold and may be relied on to suspend the capsulecentrally in the mold instead of 10 using the supporting pins 25.

Instead of having the fuse extend out through the lling opening where itmight be in the way, particularly where machine lling is relied on,there can be provided at the junction of the two 15 molded parts grooveswhich combine to form a tubular passage for the fuse so that it canextend horizontally out from the top of the mold shown in Figure 1. Therigidity of the fuse is adequate even under these conditions to supportthe cap- 20 sule substantially centrally of the chamber in the moldwhile the mold is receiving its charge of plastic material through theopening as in the case of the torpedo. This construction permits theremoval of the sprue more readily without 25 danger of damaging the fuseand insures a tighter engagement of the plastic material with the fusefor obvious reasons.

In the case of salutes, if it is desired to dip them, for instance,instead of molding the casing, 30 the fuse makes a suitable handle forthe purpose, and satisfactory salutes, as shown in Figure 6, have beenmade by dipping once or a number of times into melted stearic acidcolored if desired to give a pleasing appearance. If dipping is to beresorted to for torpedoes, they may be carried in baskets or otherwisesuitably held during vthe operation.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. In a toy torpedo, in combination, a capsule of readily deformablematerial, explosive mixture and impact igniting means therein and meansmaintaining said capsule under such compression as to prevent shiftingof the impact igniting means therein.

2. In a toy torpedo, in combination, a charge of explosive, impactigniting means mingled with said explosive and an enclosing capsuleholding the conglomerate under suiicient pressure to prevent relativeshifting of the igniting means under normal handling conditions.

3. In a toy torpedo, in combination, a charge of explosive, impactigniting means commingled therewith, an enclosing capsule closelysurroundV ing the conglomerate and a plastic casing completely enclosingsaid capsule and holding it under compression sufficient to preventrelative shifting of the igniting means under normal handlingconditions.

` 4.V In atoy torpedo, in combination, a charge of explosive, impactigniting means commingled therewith, an enclosing capsule closelysurrounding the conglomerate and a casingformed Vcom- 55 pletely aroundsaid capsule, said casing being of a plastic material which. shrinkssuiiiciently` on hardening to hold the conglomerate immobile.

5. A toy torpedo comprising, in combination, a mixture of gravel and anexplosive composition, a completely enclosing capsule therefor closelytting the mass, a casing Vof a hardened plastic which will break into neparticles on explosion, said plastic having the propertyof shrinking onYhardening so that when applied to the capsule ploded on impactcomprising in combination, a mass of explosive and gravel and acompletely enclosing unitary casing formed and shrunk tightlythereabout.

9. A toy torpedo of the type adapted to be exploded on impact comprisingin combination, a mass of explosive and gravel, a covering of tenaciousmaterial enclosing said explosive and gravel and contracting the sameand a frangible casing over the covering to increase the size of the 10torpedo.

WILLIAM L. KANN.

